Transmission / Overdrive: Strange noise

[ncalder]

I have a strange noise that seems to be coming from the engine compartment and I think it may be coming from the overdrive relay. It only happens when the truck is really warmed up and only at speeds above when the governer grounds out. It sounds like the flapping noise of a kids bicycicle wheel with something on the spokes. It is not affected by engine speed and cuts out when the governer cuts out. It doesn't come from the transmission area but rather the bulkhead area. I'm thinking I'll run the truck at speed on axle stands and have a closer listen. Any ideas? Overdrive works well -- Nick

[bosshoss61]

It is not effected by engine speed? That cuts out about half of the concerns right there........I'm thinking it's a 7 and not an ace in the spokes

[StudeRich]

Well if it stops when the Overdrive goes into free wheeling it sounds like it is in the Trans.
Sometimes noise travels around fooling you as to where they come from. I wonder if it is the O.D. Relay points bouncing and clicking?

I remember a LOT of noise coming from a firewall mounted Voltage Regular on a '59 Lark when the points were "searching", opening and closing to much possibly it was a bad Reg. and that could be the same type of sound from a Relay.

[ncalder]

I think it may be points clicking - it sounds like that. Sounds like tappets clicking but doesn't speed up with revving and cuts out at speeds below 20mph ish (governer speed)

[ncalder]

I removed the O/D fuse yesterday and the noise stopped. I'm amazed that a relay can make such a loud noise. The truck came with two other spare relays - one an old original one. I'm going to test it and hopefully use that, my experience of the reproduction electrical components is that they are junk and only work for a short time.

[gordr]

Are you running six-volt overdrive components on twelve volts? Sounds like the relay may be cutting out because it pulls too much current, and draws the voltage down. Motors and relays can "chatter" like that if their current demands exceed that which the wiring or source can supply.

[ncalder]

Its all 6 volts - but I haven't checked the voltage regulator to see the output - maybe someone put the wrong generator in way back - but I would think it would have fried everything by now.